The subject matter of the present invention relates to a digital color television system in general and more specifically to such a system in which only one of the two chrominance components I and Q is transmitted and/or recorded for each television line and digital delay means is used to delay the chrominance component of an adjacent line to enable it to be combined with that of the transmitted line to produce an output television signal having both chrominance components per line.
The television system of the present invention is especially useful in recording digital color television signals on optical records because it reduces the amount of information which must be stored on such record for each television line.
Previously it has been proposed in analog color television systems to use a delay line in the television receiver to delay one of the chrominance components so that such receiver displays a picture having television lines with both chrominance components even though only one chrominance component is transmitted per line. This European television system, called SECAM, was designed this way to reduce problems and color phase control. However, color phase control is not a problem when transmitting digital color television signals. A similar analog color television system employing an analog signal delay line is shown in U.S. Pat. No. 3,571,494 of Law, issued Mar. 16, 1971, which reduces band width requirements by sampling the analog video signal and shifting the sampling points.
It has also been proposed by K. Compaan et al in Philips Technical Review, Vol. 33, pages 178-185, 1973, No. 7, to record and playback video television signals on optical records. However, records on the order of 30 centimeters in diameter were required for storing 30 minutes of television programming. By using the television system of the present invention to record and playback a digital television signal, the amount of information to be stored is greatly reduced which of course enables a reduction in size of the records and/or increased playing time per record.